Stumbling, bumbling Rahim Moore must go.He is doomed to be known forever for his Brain Freeze against Baltimore. Yes, there were other reasons the Broncos got bounced rudely from the playoffs.But, if Denver is serious about winning a Super Bowl before quarterback Peyton Manning's 40th birthday, the Broncos must improve at safety, the weakest position on the team.Denver coach John Fox forgives Moore.Sorry, I can't.If the Broncos target any position in free agency, please, let it be safety.When the market opens on March 12, let's hope Denver is ready to pounce. In the NFL, you never know for sure which disgruntled veteran will be stuck with the dreaded franchise tag and which lucky player will be allowed to test free agency.Should the Broncos want to invest heavily on a defensive upgrade, however, they should keep their eyes on San Francisco free safety Dashon Goldson. Niners management indicates it's no certainty he will receive the franchise tag, and negotiations on a long-term deal show few signs of progress. At 28 years old, Goldson has outgrown the youthful mistakes that plague Moore.What gives Goldson a shot at the elite level in his prime is a combination of ballhawking skills and explosive hits. The downside? He took home a $6.2 million salary last season and wants to get paid. And I admit a preference for spending at the bargain end of the store in the NFL's free-agency market. For example: The reasons to admire Baltimore safety Ed Reed begin with a long list of Pro Bowl appearances, but there is way too much gray in his beard.But would I dump linebacker D.J. Williams, if the Broncos could instead make room for Goldson? In a heartbeat.